CN112646369A - Polyamide composition with reduced yellowness index - Google Patents
Polyamide composition with reduced yellowness index Download PDFInfo
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- CN112646369A CN112646369A CN202011504368.3A CN202011504368A CN112646369A CN 112646369 A CN112646369 A CN 112646369A CN 202011504368 A CN202011504368 A CN 202011504368A CN 112646369 A CN112646369 A CN 112646369A
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/32—Phosphorus-containing compounds
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K7/00—Use of ingredients characterised by shape
- C08K7/02—Fibres or whiskers
- C08K7/04—Fibres or whiskers inorganic
- C08K7/14—Glass
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2201/00—Properties
- C08L2201/02—Flame or fire retardant/resistant
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Abstract
The invention discloses a polyamide composition with a reduced yellowness index, which is prepared from the following components in parts by weight: 70-100 parts of thermoplastic polyamide, 0-30 parts of additive and 2-4 parts of disodium phosphite aqueous solution; wherein the sum of the weight parts of the thermoplastic polyamide and the additive is 100 parts, and the concentration of the disodium phosphite aqueous solution is 15-25%. According to the invention, under the condition that a conventional organic antioxidant is not used, a certain content of disodium phosphite aqueous solution is injected into polyamide, so that the yellowness index of the polyamide resin in melt extrusion can be obviously reduced.
Description
Technical Field
The invention relates to the field of high polymer materials, in particular to a polyamide composition with a reduced yellowness index.
Background
Polyamides, commonly referred to as nylons, are polymers having amide linkages in the molecular backbone. It has been widely used in textile, automotive, electronic and electrical, packaging, sports products, etc. Polyamides are generally divided into two groups, one of which is polyamides obtained by polycondensation of amino acids or ring opening polymerization of lactams, also known as AB-type polyamides, a typical representative resin of which is polyamide 6; one type is polyamide obtained by polycondensation of a dibasic acid and a diamine, also known as AABB type polyamide, and a representative resin of this type of polyamide is polyamide 66.
The dyed polyamide 6 and polyamide 66 are widely used in various industries, and in the field of electronic and electric appliances, the polyamide 66 material used as a terminal is dyed in different colors so as to be distinguished by engineering installation and maintenance personnel, and the polyamide 6 material used for electric tools and gardening tools is made into various bright color tones according to the design requirements. Unfortunately, polyamide 6 or polyamide 66 is inevitably exposed to an air environment during melt extrusion, the chemically active amide groups are susceptible to thermo-oxidative Degradation, forming chromogenic groups of the α -keto-amino structure [ Li R, Hu X. Study on dispersion medium of Polymer 6during thermal-oxidative Degradation [ J ]. Polymer Degradation and stabilization, 1998,62(3):523-528 ], with visible yellowing, and therefore, in the industrial production of light-colored or bright-colored nylon parts, the color is often unsatisfactory, and researchers have improved this defect by adding antioxidants and even weather-resistant additives, but the problem of yellowing of polyamide resins cannot be completely eliminated, although there is an improvement.
Disclosure of Invention
The invention aims to provide a polyamide composition with reduced yellowness index, which solves the problems in the prior art and can achieve good effect of reducing the yellowness index of the polyamide composition without using an organic antioxidant.
In order to achieve the purpose, the invention provides the following technical scheme:
the invention provides a polyamide composition with a reduced yellowness index, which is prepared from the following components in parts by weight:
70-100 parts of thermoplastic polyamide;
0-30 parts of an additive;
2-4 parts of disodium phosphite aqueous solution;
wherein the sum of the weight parts of the thermoplastic polyamide and the additive is 100 parts, and the concentration of the disodium phosphite aqueous solution is 15-25%.
As a further scheme of the invention: the viscosity value of the thermoplastic polyamide is 90-350ml/g, and the thermoplastic polyamide is at least one of polyamide 66, polyamide 610, polyamide 6 or copolyamide 6/66.
As a further scheme of the invention: the additive comprises at least one of a reinforcing agent and a lubricant.
As a further scheme of the invention: the lubricant is at least one of metal salt, fatty acid ester, amide, olefin wax, acidified olefin wax, oxidized olefin wax and polysiloxane.
As a further scheme of the invention: the reinforcing agent is at least one of glass fiber, talcum powder, mica sheet and wollastonite.
As a further scheme of the invention: the metal ion in the metal salt is one of alkaline earth metal, zinc, aluminum and magnesium.
As a further scheme of the invention: the number of methylene groups of the fatty acid ester and the amide is 10-44; the molecular weight of the olefin wax, the acidified olefin wax and the oxidized olefin wax is less than or equal to 3000.
The present invention also provides a process for the preparation of a polyamide composition with reduced yellowness index as defined in any one of the preceding claims, comprising the steps of:
respectively adding thermoplastic polyamide, an additive and a disodium phosphite aqueous solution into a second feeding port and a third feeding port of a first feeding port of a double-screw extruder; wherein, the injection speed of the first feeding port is set to be 50kg/h, and the injection speed of the third feeding port is set to be 1-2 kg/h.
Further, the twin-screw extruder comprises twelve temperature zones arranged in sequence: the temperature of the first zone is 200 ℃, the temperature of the second zone is 280 ℃, the temperature of the third zone is 280 ℃, the temperature of the fourth zone is 280 ℃, the temperature of the fifth zone is 280 ℃, the temperature of the sixth zone is 280 ℃, the temperature of the seventh zone is 280 ℃, the temperature of the eighth zone is 280 ℃, the temperature of the ninth zone is 280 ℃, the temperature of the tenth zone is 280 ℃, the temperature of the eleventh zone is 280 ℃, the temperature of the twelfth zone is 280 ℃, the temperature of the machine head is set to be 270 ℃, and; the first feeding port is located on the upstream side of the double-screw extruder, the second feeding port and the third feeding port are located on the downstream side of the double-screw extruder, a first pressure reduction devolatilization device is arranged between the second feeding port and the third feeding port, a second pressure reduction devolatilization device is arranged on the other side of the third feeding port, and the readings of pressure gauges of the first pressure reduction devolatilization device and the second pressure reduction devolatilization device are not greater than-0.1 MPa.
Compared with the prior art, the invention has the beneficial effects that: according to the invention, under the condition that a conventional organic antioxidant is not used, a disodium phosphite aqueous solution with a certain content is injected into polyamide, so that the yellowness index of the melt extrusion of polyamide resin can be obviously reduced; the concentration and the injection speed of the sodium phosphite aqueous solution can be controlled to effectively inhibit the amide groups from thermal-oxidative degradation, so that the thermal-oxidative stability of the polyamide composition is further improved, and the condition that the polyamide composition is easy to yellow is improved.
Detailed Description
The technical solutions in the present invention will be described clearly and completely with reference to the following embodiments, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The polyamide compositions of the following examples 1 to 6 and comparative examples 1 to 6 were prepared according to the compositions and addition amounts shown in tables 2 and 3, and it is understood that the following raw materials are merely illustrative of some specific embodiments of the present invention, so that the technical solution of the present invention is more clear, and do not represent that the present invention can only adopt the above agents, particularly according to the scope of the claims. In addition, "parts" described in examples and comparative examples mean parts by weight unless otherwise specified. The specific substances of each component in tables 2 and 3 are:
thermoplastic polyamide:
polyamide 6 with the trade name YH800, the intrinsic viscosity of 157ml/g and the terminal amino group content of 48meq/kg, which is purchased from Yueyang petrochemical Co., Ltd, Hunan;
polyamide 66, having the reference EPR27, an intrinsic viscosity of 150ml/g and a terminal amino group content of 46meq/kg, was obtained from engineering plastics, Inc., Hippocampus Hibiscus.
Disodium phosphite aqueous solution:
homemade, disodium phosphite was purchased from alatin reagent, analytically pure, CAS registry number: 13708-85-5, dissolving disodium phosphite in deionized water to make the solubility 20%.
Additive:
alkali-free E-grade glass fiber, grade: ECS 301HP, available from Chongqing International composite materials corporation;
antioxidant 1098, CAS accession No.: 23128-74-7, trade name IGNANOX 1098, from Pasteur, Germany;
antioxidant 168, CAS registry number: 31570-04-4, available from Pasteur, Germany under the trade designation IGNAOX 168;
lubricant: oxidized high-density polyethylene wax, grade: PED521, acid number 17mgKOH/g, was purchased from Claien specialty Chemicals, Inc., Germany.
A double-screw extruder: the screw rod is 35mm in diameter, the length-diameter ratio of the screw rod is 48:1, and the whole machine is divided into 12 sections of cylinders.
According to the component proportions in tables 2 and 3, polyamide 6 and polyamide 66 are premixed and then added into a first feeding port of a double-screw extruder, and the feeding speed is set to be 50 kg/h; the additive is fed from a second feeding hopper, the second feeding hopper is arranged at the position of the 8 th section of the cylinder body, and the extrusion temperature is set as follows in sequence from the first section: 200 ℃, 280 ℃, 270 ℃ for the head temperature and 300rpm for the screw speed. The disodium phosphate aqueous solution is injected from the third feeding port, and the injection speed is set to be shown in tables 2 and 3. The pressure gauge reading of the two sets of pressure reduction devolatilization devices is-0.1 MPa. The composition is subjected to melt plasticization, extrusion and grain cutting, and injection molding is carried out according to the injection molding conditions shown in Table 1 to obtain a 3mm color block, and the test results are shown in tables 2 and 3:
table 1: parameters of injection molding
And (3) storing the color blocks in a constant temperature and humidity box (23 ℃, 50% humidity) for 48h, taking out, measuring the yellowness index YI by using a Konika minolta spectrophotometer CM-5, measuring each sample for 5 times, and taking the average value of the yellow index YI.
TABLE 2 raw material component ratios and yellowness index of polyamide compositions of examples 1 to 6
TABLE 3 raw material component ratios and yellowness index of comparative examples 1 to 6 polyamide compositions
As can be seen from tables 2 and 3, the polyamide composition obtained in example 1 has a yellowness index of 4.8, which is significantly lower than the roughness index of 9.8 of comparative example 1; the yellowness index of the polyamide composition obtained in example 4 is 3.9, which is obviously lower than the yellowness index of 8.7 of comparative example 4, and therefore, the yellowness index can be effectively reduced by adding the disodium phosphite aqueous solution and keeping a certain injection speed; as can be seen from comparative example 2 and example 2, the yellowness index of the polyamide composition to which the antioxidant and the lubricant were added was lower than that of the polyamide composition to which the aqueous disodium phosphite solution was added; from example 3 and comparative example 3, it can be seen that the addition of aqueous disodium phosphite solution can effectively reduce the barrenness index and is also suitable for glass fiber reinforced polyamide compositions; as can be seen from comparative example 5 and example 5, the effect of improving the yellowness index is not obvious when the injection speed of the disodium phosphite aqueous solution is too slow; as can be seen from example 6 and comparative example 6, too fast an injection rate of the aqueous disodium phosphite solution was not significant in the improvement of the waste index.
Although the present description is described in terms of embodiments, not every embodiment includes only a single embodiment, and such description is for clarity only, and those skilled in the art should be able to integrate the description as a whole, and the embodiments can be appropriately combined to form other embodiments as will be understood by those skilled in the art.
Therefore, the above description is only a preferred embodiment of the present application, and is not intended to limit the scope of the present application; all changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.
Claims (10)
1. The polyamide composition with the reduced yellowness index is characterized by being prepared from the following components in parts by weight:
70-100 parts of thermoplastic polyamide;
0-30 parts of an additive;
2-4 parts of disodium phosphite aqueous solution;
wherein the sum of the weight parts of the thermoplastic polyamide and the additive is 100 parts, and the concentration of the disodium phosphite aqueous solution is 15-25%.
2. A polyamide composition with reduced yellowness index according to claim 1, characterized in that the viscosity number of the thermoplastic polyamide is 90-350ml/g and the thermoplastic polyamide is a lactam with 7 to 13 ring members.
3. Polyamide composition with reduced yellowness index according to claim 1, characterized in that said thermoplastic polyamide is at least one of polyamide 66, polyamide 610, polyamide 6 or copolyamide 6/66.
4. The polyamide composition having a reduced yellowness index according to claim 1, wherein the additive comprises at least one of a reinforcing agent and a lubricant.
5. The polyamide composition having a reduced yellowness index of claim 4, wherein the lubricant is at least one of a metal salt, a fatty acid ester, an amide, an olefin wax, an acidified olefin wax, an oxidized olefin wax, and a polysiloxane.
6. The polyamide composition with reduced yellowness index according to claim 4, wherein the reinforcing agent is at least one of glass fiber, talc, mica flakes and wollastonite.
7. The polyamide composition of claim 5, wherein the metal ion of the metal salt is one of an alkaline earth metal, zinc, aluminum, and magnesium.
8. The polyamide composition having a reduced yellowness index according to claim 5 wherein the fatty acid ester and the amide each have a methylene number of from 10 to 44; the molecular weight of the olefin wax, the acidified olefin wax and the oxidized olefin wax is less than or equal to 3000.
9. Process for the preparation of a polyamide composition with reduced yellowness index according to any one of claims 1 to 8, characterized in that it comprises the following steps:
respectively adding thermoplastic polyamide, an additive and a disodium phosphite aqueous solution into a second feeding port and a third feeding port of a first feeding port of a double-screw extruder; wherein, the injection speed of the first feeding port is set to be 50kg/h, and the injection speed of the third feeding port is set to be 1-2 kg/h.
10. The method of claim 9, wherein the twin-screw extruder comprises twelve temperature zones arranged in sequence: the temperature of the first zone is 200 ℃, the temperature of the second zone is 280 ℃, the temperature of the third zone is 280 ℃, the temperature of the fourth zone is 280 ℃, the temperature of the fifth zone is 280 ℃, the temperature of the sixth zone is 280 ℃, the temperature of the seventh zone is 280 ℃, the temperature of the eighth zone is 280 ℃, the temperature of the ninth zone is 280 ℃, the temperature of the tenth zone is 280 ℃, the temperature of the eleventh zone is 280 ℃, the temperature of the twelfth zone is 280 ℃, the temperature of the machine head is set to be 270 ℃, and; the first feeding port is located on the upstream side of the double-screw extruder, the second feeding port and the third feeding port are located on the downstream side of the double-screw extruder, a first pressure reduction devolatilization device is arranged between the second feeding port and the third feeding port, a second pressure reduction devolatilization device is arranged on the other side of the third feeding port, and the readings of pressure gauges of the first pressure reduction devolatilization device and the second pressure reduction devolatilization device are not greater than-0.1 MPa.
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| CN202011504368.3A CN112646369A (en) | 2020-12-18 | 2020-12-18 | Polyamide composition with reduced yellowness index |
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| CN202011504368.3A CN112646369A (en) | 2020-12-18 | 2020-12-18 | Polyamide composition with reduced yellowness index |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109679340A (en) * | 2018-12-27 | 2019-04-26 | 会通新材料(上海)有限公司 | A kind of 56 composition of polyamide promoting thermal stability and crystalline rate |
| CN111117218A (en) * | 2019-12-31 | 2020-05-08 | 会通新材料(上海)有限公司 | Polyamide composition with improved color fastness after hot baking and application thereof |
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- 2020-12-18 CN CN202011504368.3A patent/CN112646369A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109679340A (en) * | 2018-12-27 | 2019-04-26 | 会通新材料(上海)有限公司 | A kind of 56 composition of polyamide promoting thermal stability and crystalline rate |
| CN111117218A (en) * | 2019-12-31 | 2020-05-08 | 会通新材料(上海)有限公司 | Polyamide composition with improved color fastness after hot baking and application thereof |
Non-Patent Citations (1)
| Title |
|---|
| 化学工业部合成材料老化研究所, 化学工业出版社 * |
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